import java.util.Scanner;

// SwSE$3454356DD$$#E#eswsxxsssAAWDxxdderfvcRFER65645hbg^^%%^UnbnvccTRChnyvcxcvVCFR
public class SnakeString {
    public static void main(String[] args) {
        String[] char1 = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"};
        String[] char2 = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"};
        Scanner scanner = new Scanner(System.in);
        String input = scanner.nextLine();
        StringBuilder result = new StringBuilder();
        for (int i = 0; i < char1.length; i++) {
            while (input.contains(char1[i]) && input.contains(char2[i])) {
                StringBuilder temp = new StringBuilder();
                temp.append(char1[i]).append(char2[i]);
                input = input.replaceFirst(char1[i], "@");
                input = input.replaceFirst(char2[i], "@");
                int j = i + 1;
                while (j < char1.length && input.contains(char1[j]) && input.contains(char2[j])) {
                    temp.append(char1[j]).append(char2[j]);
                    input = input.replaceFirst(char1[j], "@");
                    input = input.replaceFirst(char2[j], "@");
                    j++;
                }
            }
        }
        System.out.println(result.toString().equals("") ? "Not Found" : result.toString());
    }
}
